As it is generally known, a data storage array contains one or more non-volatile storage devices, such as magnetic disk drives, electronic flash drives, and/or optical drives, and is used by one or more host machines to store and retrieve data on the non-volatile storage devices contained therein. Specifically, storage arrays service host I/O operations that arrive from the host machine and that specify logical storage objects that are to be written, read, created, or deleted. Storage arrays include hardware and software that receives and manages incoming host I/O operations, and that organizes and secures the host data that is stored on behalf of the host machine on the non-volatile storage devices contained in the storage arrays.
Fault tolerance is an important consideration for data storage systems. Some previous systems have operated to replicate logical storage objects across multiple storage arrays, in order to provide certain kinds of fault tolerance.